Alexis de Tocqueville in Democracy in America back in 1835:
The Constitution of the United States resembles those beautiful creations of human industry which insure wealth and renown to their inventors, but which are profitless in other hands. This truth is exemplified by the condition of Mexico at the present time. The Mexicans were desirous of establishing a federal system, and they took the Federal Constitution of their neighbors, the Anglo-Americans, as their model, and copied it entirely. But although they had borrowed the letter of the law, they could not introduce the spirit and the sense which give it life. They were involved in ceaseless embarrassments by the mechanism of their double government; the sovereignty of the States and that of the Union perpetually exceeded their respective privileges, and came into collision; and to the present day Mexico is alternately the victim of anarchy and the slave of military despotism. … To the south, the Union has a point of contact with the empire of Mexico; and it is thence that serious hostilities may one day be expected to arise. But for a long while to come, the uncivilized state of the Mexican people, the depravity of their morals, and their extreme poverty, will prevent that country from ranking high amongst nations.